dob or explorer?

[Steve Swancott]

A quick question about dobs.

I take it you cant track the object say with a with a slow motion knob (basicly because it hasn't got one). But how do you 'keep up' with say mars? I've only seen a dob in pictures so i take it that it goes 360 degrees on it's base i dont know unless there is a way to keep up with objects because i think it will just swing too easily...

thanks

steve

[onesmallstep]

Hi

Dobs track manually so the user pushes the scope in the direction of the object being observed. The Dob base is solid so the scope will only move when deliberately pushed or accidentally knocked but that's the case with most scopes (most astronomers have tripped over tripod legs in their time). Magnification is also a factor as the higher the mag, the more pronounced the Earth's rotation is and the faster an object will move across the field of view.

HTH!

[RikM]

It shouldn't swing too easily. The good thing about a Dob (at least in theory) is that there is a little bit of 'friction', but no 'sticktion'. This means you can move it smoothly and easily to follow the object you are viewing. This becomes second nature after a very short time; you just push or pull the tube to wherever you want. But there is still a little bit of friction in the system, so it stops still, is nice and steady and doesn't move when you are not pushing it.

[Moonshane]

all the above, plus because it is very solid, you don't get the wobble you get with many undermounted EQ scopes. a dob settles down almost instantly.